Catheters, and more particularly, balloon catheters have been used to treat stenosis of a vascular or other anatomical tubular structure. In one such procedure, called percutaneous transluminal angioplasty or PTA, a balloon catheter is inserted into a vessel and advanced to the site of the stenosis or lesion where the balloon is inflated against the lesion. Pressure applied to the stenosis by the surface of inflated balloon compresses the lesion, pushing it radially outward and widening or restoring the luminal diameter of the vessel. Various forms of PTA have been used to treat peripheral arterial stenosis, coronary lesions and other non-vascular tubular structures such as biliary ducts.
Notwithstanding the importance of PTA procedures in restoring normal blood flow to an anatomical region, one problem associated with PTA procedures is the undesired re-growth of the lesion, commonly known as re-stenosis. Re-stenosis, a re-narrowing of the vessel lumen, usually occurs within three to six months after the angioplasty procedure. Studies have demonstrated a re-stenosis rate after angioplasty in up to 50% of patients treated. Although the use of stents has reduced the re-stenosis rate to approximately 30% of the procedures, re-stenosis remains a significant clinical problem, particularly for those patients whose general health is not conducive to repeat interventional procedures.
The main cause of re-stenosis following angioplasty procedures is due to vessel wall trauma created during the procedure. Evidence has shown that scar tissue forms as endothelial cells that line the inner wall of the blood vessel regenerate in response to the vessel wall injury created during angioplasty. An overgrowth of endothelial cells triggered by the trauma leads to a re-narrowing of the vessel and eventual re-stenosis of the treated area. Cutting wire balloon catheters, also known in the art, have been used to “score” a stenotic lesion in a more controlled, precise manner. Although it is contemplated that scoring a lesion will lead to less procedural vessel trauma, endothelial cell re-growth and re-stenosis, to date there are no studies that effectively demonstrate this.
Recently, advances in stent technology have included drug-eluting stents which are intended to reduce the occurrence of re-stenosis even further. These types of stents are coated with a drug designed to suppress growth of scar tissue along the inner vessel wall over an extended period of time. The drug is slowly released or eluted, thus reducing the occurrence and extent of re-stenosis when compared with bare stents. Although shown to be effective in further reducing re-stenosis, there are several known problems with drug-eluting stents including an increased risk in some patient populations of localized blood clots after the drug has been completely eluted, usually after six or more months. Clot formation in the coronary system can lead to heart attack and death. Other problems include stent fracture and other known risks associated with long-term implants.
Therefore, it is desirable to provide a device and method for the prevention of re-stenosis associated with primary angioplasty and/or stenting procedures that is safe, easy and does not require placement of a stent.